一种区域格点三维变分分析方案--基本框架和初步试验

给出一种区域格点三维变分分析方案的基本框架.对方案中阶数巨大的背景场误差协方差矩阵加以处理,选用位势高度和风场非平衡部分的纬向风速、经向风速作为分析变量,减少矩阵阶数;进行变量变换,避免矩阵求逆;然后,采用与最优插值方案相似的水平和垂直方向可分离的理想相关模型,在水平方向上用递归滤波器代替矩阵运算,从而实现变分分析方案的求解.用单个和理想分布观测资料对方案测试,并进行实例试验,得到很好的计算结果.

A Regional Grid Three-Dimensional Variational Analysis Scheme-Basic Construction and Preliminary Tests

The basic construction of a regional grid three-dimensional variational (3D-Var) analysis scheme is described. To deal with the covariance matrix of background errors B, three skills are used. These skills include choosing suitable analysis variables to simplify computations of matrix B, doing a variable transformation to avoid matrix inversion and separating univariate correlation matrix into horizontal and vertical parts to use recursive filter instead of matrix computations in the horizontal. Then 3D-Var analyses can be carried out. This scheme is tested through a single observation, ideal distributed observations and real observation data. The results are very satisfying.